Human health and disease in a microbial world

Humans and other mammals have co-evolved with trillions of microorganisms (the microbiota), whose aggregate genomes (the microbiome) contribute functions that are not encoded by our own human genome. Recent developments in the emerging field of metagenomics have enabled an unprecedented description of organismal, genetic, transcriptional, proteomic, and metabolic diversity across a wide range of body habitats, spawning multiple ongoing international human microbiome projects. These largely sequencing-driven studies, along with mechanistic studies in vitro and in animal models, have emphasized the role the human microbiome plays in health and disease, including inflammatory bowel disease, metabolic syndrome, autoimmune disorders, and even cancer.